Marriage Law Belgium
MARRIAGE

In order to get married in Belgium, one of the parties must reside in the country. There is no specific period of residence, but several weeks are generally necessary for completion of the required paperwork. If neither of the parties has a permanent residence in Belgium, one of them may establish a residence for this purpose.

Upon arrival in Belgium, the party must register with the communal authorities in the district of residence and request a Bewijs van Woonst voor Huwelijksdoeleinden/ Certificat de Domicile pour mariage (Certificate of Residence for Marriage Purposes).

APPLICATIONS AND/OR DOCUMENTS REQUIRED

The Original copies of the following may be required:
Certified copy of the birth certificateCertificate of residence showing full name, place and date of birth, last legal residence, nationality and marital status of the individuals. The Belgian communal authorities will issue this certificate to the party registered in Belgium. The party not registered in Belgium must obtain it from the authorities of his or her last place of residenceIf previously married, then a certified copy of the final divorce decree or the death certificate of the former spouse.
If the divorce decree does not indicate the date on which the divorce became final, a statement from the court which pronounced the divorce must also be produced
All official documents issued in a foreign country must be authenticated by means of the Apostille.
If the documents are written in a language other than Dutch, French or German, they must be translated by a sworn translator
WAITING PERIOD
The marriage may be performed ten days after posting of the banns.

https://www.helplinelaw.com/article/belgium/46

https://be.usembassy.gov/u-s-citizen-services/additional-res...